oarlock vs tholepin

oarlock and tholepin both are nouns.

Word	Noun	Adjective	Verb	Adverb
oarlock	Yes	No	No	No
tholepin	Yes	No	No	No

As nouns, oarlock and tholepin are synonyms defined as:

oarlock and tholepin: a holder attached to the gunwale of a boat that holds the oar in place and acts as a fulcrum for rowing

Other synonyms of oarlock include peg, pin, rowlock, thole.

oarlock (noun)	tholepin (noun)
a holder attached to the gunwale of a boat that holds the oar in place and acts as a fulcrum for rowing	a holder attached to the gunwale of a boat that holds the oar in place and acts as a fulcrum for rowing